Abstract: Methods, systems, and apparatus, including computer program products for structured content ranking. In an aspect, a method includes, receiving, at a controller, an alternating current signal; determining harmonic values that describe a fundamental frequency component of the alternating current signal and harmonic components of the alternating current signal; accessing, by the controller, control data that defines a relation of harmonic values to operational instructions, wherein each operational instruction, when supplied to an inverter, causes the inverter to perform an operation defined by the operational instruction; selecting, by the controller, an operational instruction from the operational instructions, the selected operational instruction based on the harmonic values and the control data; and providing, by the controller, the selected operational instruction to the inverter to cause the inverter to perform the operation defined by the selected operational instruction.

Abstract: A power conversion unit includes power converters arranged sequentially to each other to convert input power that is provided at an input of the power conversion unit to output power. A set of first capacitors are arranged in series with each other and include, for each power converter, a first capacitor that is arranged in parallel with an associated power converter. Each first capacitor is also arranged to store a portion of the input power. A set of second capacitors are connected in series with each other and include a second capacitor connected between each pair of sequential power converters in the sequence. The set of second capacitors are arranged to balance the portion of the input power stored by each first capacitor.